October 24, 2011

Scientists Reveal How First Supernova Ever Recorded Occurred

NASA said on Monday that its Spitzer Space Telescope and Wide-field Infrared Survey Explorer (WISE) have revealed how the first supernova ever recorded occurred.

The space agency said that the new findings show that the explosion took place in a hollowed-out cavity, allowing material expelled by the star to travel much faster and father.

"This supernova remnant got really big, really fast," Brian J. Williams, an astronomer at North Carolina State University in Raleigh, said in a press release. "It's two to three times bigger than we would expect for a supernova that was witnessed exploding nearly 2,000 years ago. Now, we've been able to finally pinpoint the cause."

The findings reveal that the event is a "Type Ia" supernova and was created by the relatively peaceful death of a star like our sun. The supernova then shrank into a dense star called a white dwarf.

"A white dwarf is like a smoking cinder from a burnt-out fire," Williams said in a press release. "If you pour gasoline on it, it will explode."

The scientists also found that a white dwarf can create a cavity around it before blowing up in a Type Ia event.

The team used Spitzer and Wise to measure the temperature of the dust making up the RCW 86 remnant at about minus 325 degrees Fahrenheit.

The team then calculated how much gas must be present within the remnant to heat the dust to those temperatures.

Scientists initially suspected that RCW 86 was the result of a core-collapse supernova, which is the most powerful type of explosion.

However, other evidence showed that the object consisted of high amounts of iron, which is a sign of a Type Ia blast.

"Modern astronomers unveiled one secret of a two-millennia-old cosmic mystery only to reveal another," Bill Danchi, Spitzer and WISE program scientist at NASA Headquarters in Washington, said in a press release. "Now, with multiple observatories extending our senses in space, we can fully appreciate the remarkable physics behind this star's death throes, yet still be as in awe of the cosmos as the ancient astronomers."

The study was published in the Astrophysical Journal online.

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Image 1: This image combines data from four different space telescopes to create a multi-wavelength view of all that remains of the oldest documented example of a supernova, called RCW 86. Image credit: NASA/ESA/JPL-Caltech/UCLA/CXC/SAO

Image 2: Infrared images from NASA's Spitzer Space Telescope and Wide-field Infrared Survey Explorer (WISE) are combined in this image of RCW 86, the dusty remains of the oldest documented example of an exploding star, or supernova. Image credit: NASA/JPL-Caltech/UCLA